Sleep duration and mortality.
Article Type: Report
Subject: Mortality (Australia)
Mortality (Forecasts and trends)
Mortality (Demographic aspects)
Sleep (Health aspects)
Author: Murphy, Kathleen
Pub Date: 03/22/2011
Publication: Name: Australian Journal of Medical Herbalism Publisher: National Herbalists Association of Australia Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2011 National Herbalists Association of Australia ISSN: 1033-8330
Issue: Date: Spring, 2011 Source Volume: 23 Source Issue: 1
Topic: Event Code: 010 Forecasts, trends, outlooks Computer Subject: Market trend/market analysis
Geographic: Geographic Scope: Australia Geographic Code: 8AUST Australia
Accession Number: 254971780
Full Text: Cappuccio F, D'Elia L, Strazzullo P et al. 2011. Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep 33:5;585-92.

Sleep patterns of quantity and quality are affected by a variety of cultural, social, psychological, behavioural, pathophysiological and environmental influences. Lack of sleep exerts deleterious effects on a variety of systems with detectable changes in metabolic, endocrine and immune pathways. Over recent decades there has been growing evidence to suggest that too little sleep and too much sleep are associated with adverse health outcomes including total mortality, cardiovascular disease, type II diabetes, hypertension, respiratory disorders and obesity in both children and adults.

This study systematically reviewed published prospective population based studies, carried out a meta analysis to assess whether the global evidence supports a relationship between either short or long duration of sleep and all cause mortality, and obtained a quantitative estimate of the risk to assess the consistency and potential public health relevance. Overall the meta analysis included 1 382 999 participants from 8 different countries contained within 16 studies reporting on 27 cohorts.

In the pooled analysis, short duration of sleep (25 cohorts from 15 studies, n = 1 381 324 with 112 163 deaths) was associated with greater risk of death (RR 1.12; 95% CI 1.06 to 1.18, P <0.01). Long duration of sleep (27 cohorts from 16 studies, n = 1 382 999 with 112 566 deaths) was associated with a greater risk of death (1.30; [1.22-1.38]; P <0.0001). Short sleep effect was consistent in younger (<60 years) and older ([greater than or equal to] 60 years) cohorts in men and women. The effect of long sleep was stronger in older than younger cohorts (heterogeneity P = 0.01), increased with the definition of long duration of sleep from >8 h, greater than or equal to] 9 h and [greater than or equal to] 10 h per night (heterogeneity P = 0.0004).

This analysis indicates that short sleepers (commonly <7 h per night, often <5 h per night) have a 12% greater risk, and long sleepers (commonly >8 or 9 h per night) a 30% greater risk of dying than those sleeping 7 to 8 h per night. The researchers proposed a number of mechanisms that may contribute to these results.

Future studies should be designed to answer the question whether sleep duration is a cause or simply a marker of ill health. Indirect evidence seems to suggest to date that sustained sleep deprivation may trigger biological mechanisms contributing to the deterioration of health status, whereas long duration of sleep may be a powerful additional marker of ill health.

Kathleen Murphy mnhaa
Gale Copyright: Copyright 2011 Gale, Cengage Learning. All rights reserved.